What is a pop-up ad?
Pop-up ads are small windows that open automatically on your screen. They often (but not always) display advertising, which can be from legitimate businesses, but also might be scams or dangerous software.
Pop-up ads can be part of a phishing scam designed to trick you into revealing sensitive personal or financial information as you surf the web.
If pop-up ads open even when you're not surfing the web, your computer might be infected with spyware.
Not all pop-ups are bad: Some websites use pop-up windows for specific tasks. You might need to view the window in order to complete that task.
Microsoft Security Essentials can help protect against dangerous pop-up ads
Microsoft Security Essentials is a free program that helps protect your computer against dangerous pop-up ads, spyware, viruses, and other unwanted software. For more information, see Microsoft Security Essentials.
Use a pop-up blocker
We recommend that you turn on a pop-up blocker when you surf the web, and turn it off only for those rare cases where you need to interact with a pop-up on a site to complete a task. Internet Explorer includes a pop-up blocker.
To turn on Pop-up Blocker, click the Tools button, and then click Pop-up Blocker.
To turn off Pop-up Blocker, click the Tools button, and then click Turn Off Pop-up Blocker.
To download Internet Explorer, visit the Internet Explorer website.
If the Internet Explorer Pop-up Blocker blocks a pop-up window from a site that you trust, you can decide to temporarily allow pop-up ads from that site or to always allow pop-ups from that site.
To adjust the settings in the Internet Explorer Pop-up Blocker
Click the Tools button, and then click Pop-up Blocker.
Click Pop-up Blocker Settings